Flood control

There are lessons to be learnt from across the world on floods and flood alleviation. There is a growing realisation that nature is powerful and not always to be controlled. Floods are powerful and also play an essential role in freshwater ecosystems and geomorphological processes.

As hinted above, there are many perspectives to flooding:
  • Residents and business interests. Floods are a cause of concern because of the potential for damage and the associated costs to property as well as personal safety.
  • River management interests. Floods are a problem for which a solution can be found, using technology at an acceptable cost.
  • Natural heritage interests. Floods are an essential natural process within ecological and geomorphological systems; flood engineering works can alter these systems to the detriment of habitats and wildlife.
Floodplains are natural ‘safety valves’ able to reduce the energy of vast quantities of water safely. The reality and inevitability of floods is now recognised by the planning authorities, which are now applying restrictions to any further floodplain developments.
  • The management of neighbouring land and riverside vegetation has an important impact on the rate and volume of water entering a water channel. Centuries of removal of the natural tree cover and reduction of vegetation through intensive grazing, and decades of road building and development close to rivers, can have damaging effects.
  • Open and/or compacted ground leads to an increased volume and intensity of water runoff during heavy rain or snowmelts. This can lead to an increase in peak river flow and floods.
Under more natural conditions, the water would have time to percolate through covering vegetation into the soil, before returning to the water channel.

Photography: Spey in flood at Dulnain Mouth (CNPA)